The invention refers to a closure cap for infusion and transfusion bottles, having a rim cap which surrounds a rim neck of the bottle and has a central cutout which is closed by the central region of a plastic lid in such a manner that an annular region of the plastic lid engages below the edge of the central cutout.
A closure cap of this type is known from Federal Republic of Germany Pat. No. 20 40 937. By the pulling off of the plastic lid the central cutout is free for introducing an injection needle, transfusion fitting or the like through a disk-shaped closure stopper inserted in the rim neck. For reasons of the indispensable aseptic character of the transition region between plastic lid and rim cap there must be present, on the one hand, an effective septic barrier which is provided there by a sealing joint of the nature of an annular groove. The form-fitting surrounding of the central cutout by the viscoelastic plastic of the lid requires, on the other hand, a relatively large opening force, for which reason a pull tab which is adapted approximately to the area of the central cutout is developed on the top of the plastic lid. This tab lies decentrally on and extends, cantilevered above the said central region in a close parallel neighboring relationship to the top side of the lid. This, however, requires complicated measures of molding technique. In order to bring the pull tab into a position suitable for gripping, it must be bent off by an angle of practically about 90 degrees. This entails a not inconsiderable risk of it being torn off; without such a pull tab the removal of the plastic lid is fundamentally still possibly only by the use of auxiliary tools. However, this can lead to damage to the neck of the bottle.
It is the object of the present invention so to develop a closure cap of this type in a manner which is simpler to manufacture and more dependable in use, without any sacrifice in the sealing properties, in such a manner that the closure cap can be removed more easily despite the fact that it is more firmly attached to the rim cap.